\begin{tikzpicture}
	\pgfmathsetmacro{\r}{2}
	\tkzDefPoints{0/0/O}
	\tkzDefPoint(15:\r){A}
	\tkzDefPoint(105:\r){B}
	\tkzDefPoint(-10:\r){C}
	\tkzDefPoint(-100:\r){D}

	\tkzDrawSegments(O,A  O,B  O,C  O,D)
	\tkzMarkRightAngle(A,O,B)
	\tkzMarkRightAngle(C,O,D)
	\tkzLabelPoints[left](O)
	\tkzLabelPoints[below](C)
	\tkzLabelPoints[right](A, B, D)
\end{tikzpicture}

